This dataset contains two phases of research. The first dataset includes several variables that were sampled across aspen stands in the Santa Rosa, Ruby, and Jarbidge mountain ranges (Great Basin, Northern Nevada, USA) in 2010 and 2011. Across 101 aspen sites, several plot-level attributes were collected (e.g. elevation, slope, aspen stand type). For each plot, data describing live trees (both those less than 7.5 cm diameter and those greater than/equal to 7.5 cm) are included, such as species, diameter, and age. The data set also includes information for dead trees greater than/equal to 7.5 cm diameter (e.g. species, location, diameter). The second dataset includes tree ring measurements (for live trees greater than/equal to 7.5 cm diameter) and monthly climate data for a subset of sites (n = 20) that were included in the first phase. For this subset of 20 sites, we analyzed the relationship between tree ring width measurements and climate variables. The climate variables represent monthly total precipitation, average temperature, and climatic moisture index values by year for the period of record.